Netopia R2121 - Manual (Page 234)

C-6 User’s Reference Guide
There are two schemes for distributing the remaining IP addresses:
■ Manually give each computer an address
■ Let the Netopia R2121 automatically distribute the addresses
These two methods are not mutually exclusive; you can manually issue some of the addresses while the rest
are distributed by the Netopia R2121. Using the Router in this way allows it to function as an address ser ver.
One reason to use the Netopia R2121 as an address ser ver is that it takes less time than manually distributing
the addresses. This is par ticularly true if you have many addresses to distribute. You only need to enter
information once, rather than having to repeatedly enter it on each host separately. This also reduces the
potential for misconfiguring hosts.
Another reason to use the Netopia R2121 as an address ser ver is that it will only distribute addresses to hosts
that need to use them.
All Netopia R2121s come with an integrated Dynamic Host Control Protocol (DHCP) ser ver. Some routers also
come with a Macintosh Internet Protocol (MacIP) ser ver. These ser vers provide a means of distributing IP
addresses to either a Mac or PC workstation as needed.
When setting up the DHCP or MacIP ser vers in the Netopia R2121, it is necessar y to understand how
workstations lease, renew, and release their IP addresses. This information will be helpful in determining
dynamic address allocation for a network.
The term “lease” describes the action of a workstation requesting and using an IP address. The address is
dynamic and can be returned to the address pool at a later time.
The term “renew” refers to what the workstations do to keep their leased IP address. At cer tain inter vals, the
workstation talks to the DHCP or MacIP ser ver and renews the lease on that IP address. This renewal allows
the workstation to keep and use the assigned IP address until the next renewal period.
The term “release” refers to a situation where the workstation is no longer using its assigned IP address or has
been shut down. IP addresses can be manually released as well. The IP address goes back into the DHCP or
MacIP address pool to be reassigned to another workstation as needed.
Technical note on subnet masking
Note: The IP address supplied by the Netopia R2121 will be a unique number. You may wish to replace this
number with a number that your ISP supplies if you are configuring the router for a static IP address. The
automatic IP mask supplied by Smar tStar t is a Class C address. However, the Netopia R2121 and all devices
on the same local network must have the same subnet mask. If you require a different class address, you may
edit the IP Mask field to enter the correct address. Refer to the table below.
Number of Devices (other than
Netopia R2121) on Local Network
Largest Possible Ethernet Subnet
Mask
1 255.255.255.252
2-5 255.255.255.248
6-13 255.255.255.240
14-29 255.255.255.224